Casting Method and Casting System for Aluminium or Aluminium Alloys

ABSTRACT

In a casting method, or a casting system for aluminum, or aluminum alloys, aluminum melt is filled into a plurality of pans ( 15, 15′ ). Said pans ( 15, 15′ ) are used for treatment, if needed, and delivered to a casting station ( 20 ), in which they are subsequently emptied, and the melt is casted into semi-finished products. At least two filled pans ( 15, 15′ ) are provided in order to ensure a continuous casting operation in the casting station ( 20 ), the melt of at least one of which is drained into a mutual inflow channel ( 27 ).

The invention relates to a casting method for aluminium or aluminiumalloys according to the preamble to claim 1 and to a casting system forimplementation of the method.

It is known from EP-A-1 607 156 to use, instead of so-called in-linecasting with which the aluminium melt flows from a melting or a heatconservation furnace via a long channel to a casting station, and issubjected here to different treatments, ladles for the treatment andconveyance of aluminium melt to preferably a number of casting stations,and so to separate this process phase temporally from the actual castingoperation. The ladles filled with melt are conveyed to at least onefurther stage and treated here, and are then delivered to the castingstation where they are emptied.

The object which forms the basis of the present invention is to furtherimprove and simplify the casting method of the previously specified typeas well as a casting system for implementation of the method.

This object is achieved according to the invention by a casting methodwith the features of claim 1 and by a casting system with the featuresof claim 6.

Preferred further embodiments of the casting method according to theinvention and of the casting system according to the invention form thesubject matter of the dependent claims.

According to the invention, at the casting station at least two filledladles can be provided, a respective one of which is emptied into amutual inflow channel so that a continuous casting operation can beguaranteed. The consecutive emptying of the ladles provided can beimplemented by opening their slide closures, preferably in a controlledmanner. The ladles do not have to be conveyed to a further treatmentstation and from there to the casting station, but the treatment of thealuminium melt can advantageously be implemented in the ladle or ladlesprovided at the casting station and not yet subjected to emptying.

In the following the invention will be described in greater detail bymeans of the drawings. These show as follows:

FIG. 1—a side view of an exemplary embodiment of a casting systemaccording to the invention for aluminium or aluminium alloys; and

FIG. 2—a top view of the casting system according to FIG. 1.

FIG. 1 diagrammatically shows a casting system for aluminium oraluminium alloys with which scrap aluminium is introduced as a basematerial into a melting furnace 10. However, blocks provided forremelting could also be used as the base material. The melt produced inthe melting furnace 10 is introduced into a heat conservation chamber 12of a filling station 11 from where it is respectively filled into aladle 15 at regular intervals with the aid of an immersion pipe 13. Themelting furnace 10 can preferably be an induction furnace which has, forexample, a holding capacity of 1.75 t and in which 2 t material per hourcan be melted. From the heat conservation chamber 12 with a holdingcapacity of 3.5 t ladles with a holding capacity of 2 t can then befilled, the other 1.5 t then remaining for further charging in the heatconservation chamber 12.

It is also possible to supply liquid aluminium to the filling station 11as the base material or to fill it directly into the ladles 15.

The ladles 15 filled in the filling station 11 are preferably conveyeddirectly to a casting station 20, this being for example a continuouscasting system, known in its own right, with a plurality of moulds 21,and in which the actual casting operation takes place. According to theinvention at least two filled ladles 15, 15′ are respectively positionedat the inflow of the casting station 20 (according to the drawing twoladles are provided), of which a respective one is emptied into a mutualinflow channel 27 by opening its slide closure 25 (FIG. 1). Thealuminium melt passes into the individual moulds 21 via the inflowchannel 27.

Any possible treatment of the aluminium melt preferably takes place inthe ladle or ladles 15, 15′ provided at the casting station 20 and whichhave not yet been subjected to emptying. Accordingly, during the castingoperation the one ladle 15 containing the already treated aluminium meltis emptied, while the melt is treated in the other ladle 15′. This caninvolve the addition of alloy additions, or cleaning and homogenisation,and if necessary temperature regulation. Of course the treatment couldalready be implemented at least partially beforehand, i.e. beforepositioning the ladle at the inflow of the casting station 20 (forexample the alloy additions can already be introduced before fillinginto the ladles 15, 15′ or an additional treatment station could beprovided).

A fan wheel, for example, for injecting argon or nitrogen can beimmersed into the ladle 15′ provided at the casting station and not yetsubjected to emptying for the combined elimination of hydrogen,homogenisation and if necessary heat regulation, it also being possibleto additionally mix small quantities of chlorine into the cleaning gasin order to eliminate any alkaline traces of contamination.

As soon as the one ladle 15 is emptied (or shortly before), the slideclosure 25 of the other ladle 15′ is opened and the casting operation iscontinuously pursued, the emptied ladle 15 being replaced by a new one.Operation of the slide closures 25 is preferably controlled.

The conveyance of the ladles 15, 15′ from the filling station 11 to thecasting station 20 takes place on rails or by means of incumbent cranes(FIG. 1 only shows a supporting frame 29 for the latterly specifiedversion).

1. A casting method for aluminium or aluminium alloys wherein aluminiummelt is filled into a plurality of ladles (15, 15′), if necessary istreated in the latter, and is delivered to a casting station (20) inwhich the ladles (15, 15′) are emptied, and the melt is cast intosemi-finished products, characterised in that in order to ensure acontinuous casting operation at least two filled ladles (15, 15′) can beprovided at the casting station (20), the melt of one of whichrespectively is emptied into a mutual inflow channel (27).
 2. Thecasting method according to claim 1, characterised in that theconsecutive emptying of the ladles (15, 15′) provided takes place withcontrollable opening of their slide closures (25).
 3. The casting methodaccording to claim 1, characterised in that the treatment of thealuminium melt takes place in the ladle (15′) or ladles provided at thecasting station (20) and not yet subjected to emptying.
 4. The castingmethod according to claim 3, characterised in that alloy additions areadded to the aluminium melt in the ladle (15′) or ladles provided at thecasting station (20) and not yet subjected to emptying, or cleaning andhomogenisation and if necessary temperature regulation is implemented.5. The casting method according to claim 4, characterised in that a fanwheel for injecting argon or nitrogen can be immersed into the ladle(15′) or ladles provided at the casting station (20) and not yetsubjected to emptying for the combined elimination of hydrogen,homogenisation and if necessary heat regulation, it also being possibleto additionally mix small quantities of chlorine into the cleaning gasin order to eliminate any alkaline traces of contamination.
 6. A castingsystem for implementation of the method according to claim 1, with aplurality of ladles (15, 15′) which can be filled with the aluminiummelt at a first filling station (11) and which can be conveyed to acasting station (20) and can be emptied at the latter by opening theirslide opening (25), means being provided for any treatment of thealuminium melt before casting, characterised in that at least two filledladles (15, 15′) can be positioned at the casting station (20), one ofwhich can respectively be emptied into a mutual inflow channel (27). 7.The casting system according to claim 6, characterised in that the meansfor any treatment of the aluminium melt are assigned to the ladles (15,15′) that can be positioned at the casting station (20).
 8. The castingsystem according to claim 6, characterised in that rails or cranes areprovided for conveying the ladles (15, 15′) from the filling station(11) to the casting station (20).
 9. The casting system according toclaim 7, characterised in that rails or cranes are provided forconveying the ladles (15, 15′) from the filling station (11) to thecasting station (20).
 10. The casting method according to claim 2,characterised in that the treatment of the aluminium melt takes place inthe ladle (15′) or ladles provided at the casting station (20) and notyet subjected to emptying.
 11. The casting method according to claim 10,characterised in that alloy additions are added to the aluminium melt inthe ladle (15′) or ladles provided at the casting station (20) and notyet subjected to emptying, or cleaning and homogenisation and ifnecessary temperature regulation is implemented.
 12. The casting methodaccording to claim 11, characterised in that a fan wheel for injectingargon or nitrogen can be immersed into the ladle (15′) or ladlesprovided at the casting station (20) and not yet subjected to emptyingfor the combined elimination of hydrogen, homogenisation and ifnecessary heat regulation, it also being possible to additionally mixsmall quantities of chlorine into the cleaning gas in order to eliminateany alkaline traces of contamination.